Three phase power is popular in data centers to minimize the cost of the cables delivering that power.
And here are three main phase power principles and challenges. That’s according to a new report from Server Technology that asserts the principles of 3-phase power are not always well understood by the installer. This paper discusses the importance of load balancing across phases and how using PDUs having alternating phase outlets simplifies the load balancing process.
Load balancing, according to the report, is critical in these applications for multiple reasons:
- If the three phases are not balanced, heat is generated resulting in higher cooling costs.
- Unbalanced loads lead to inefficiency and higher power bills.
- High loads on a single phase means greater chance of tripping either a PDU or upstream breaker, and losing power at the rack
“Good practice in the data center is to install rack mounted equipment so that the current draw is similar on each branch. This is relatively easy if the rack is filled with only one type of device,” Server Technology states.
But often, this isn’t the case.
According to the report, mixed devices such as switches, storage devices, blade servers and different brands and types of 1U/2U/3U servers can create a “crazy mesh” of power cables in the back of the rack, potentially hindering airflow and increasing heat problems. And the move to higher density racks that demand more kilowatts of power are cause for even more complex PDUs — but, as Server Technology points out, the power draw still must be evenly distributed across these branches.
Three-phase power distribution at the rack level traditionally meant that power was divided into separate branches. Load balancing and cabling can be difficult. Alternating phased power on a per-receptacle basis provides tangible benefits in the form of simplified cabling, better airflow, better load balancing and greater efficiencies. — Server Technology
That said, according to the report, “a solution to these issues is to use an alternating phase PDU.”
“These specially designed PDUs alternate the phased power on a per-outlet basis instead of a per-branch basis. An example of these products can be seen below,” Server Technology explains.
Download the new report, “Alternating Phase — A New Look at 3-Phase Power Distribution” to further explore the challenges, solutions and opportunities for three phase power, used in data centers to support high density IT applications.